Centrifugal governor



1954 w. A. HATTERY CENTRIFUGAL GOVERNOR 2 Sheets-Sheet L Filed Sept. 22, 1951 INVENTOR WOLFE A. HATTERY BYZL W ATTORNEY Dec. 21, 1954 w HATTERY 2,697,763

CENTRIFUGAL GOVERNOR Filed Sept. 22, 1951 2 Sheets-Sheet z FIG. 3

INVENTOR WOLFE A. HATTERY ATTORNEY United States Patent 0 CENTRIFUGAL GOVERNOR Wolfe A. flattery, Chicago, Ill-., as'signor to Teletype Corporatien, Chicago, Ill.,'a corporation of Delaware Application September 22, 1951, Serial No. 247,852 14 Claims. (Cl. 200-80) This invention pertains to centrifugal governors and more particularly to a mechanism for adjusting a pair of governor contacts to operate at various rated speeds.

Centrifugally operated governors have heretofore been employed to regulate the speed of operation of various types of electric motors. It is the general practice to provide a pair of governor contacts, one of which is controlled by centrifugal force, and to connect these contacts within the regulating circuit of a motor whose speed it is desired to regulate Within prescribed limits. Various devices and mechanisms have been devised to vary the speed at which the governor contacts open or close. More specifically these devices have taken the form of means for regulating the spring tension applied to the centrifugall'y actuated governor contact or means for adjusting the distance ernor contact and the axis of rotation of the governor. It has been found that the rated speed at which the governor contacts operate may be also controlled by orienting the governor contacts in respect to the axis of rotation of thegovernor to vary the direction in which the component of centrifugal force, tending to open the contacts, is directed.

It is a primary object of this invention to provide a centrifugal governor wherein the rated speed at which the governor operates may be varied by changing the direction of application of the effective component of centrifugal force acting on a movable governor contact.

It is a further object of this invention to provide a simple and economical arrangement of mechanical elements for effecting the movement of the governor contacts with respect to the axis of rotation of the governor to vary the rated speed at which the governor operates.

A turther and more specific object of the present invention is to provide a distinctive mounting for the governor contacts which may be rotated through the in-' strumentalit'y of a linkagemechanism to'rapidlychange the rated speed at which" thego'vernor contacts operate.

It is a further feature of this invention to provide a centrifugal type governor which may be rapidly and accugately adjusted to operate over a wide range of rated spee s. 7

With theseand other objects in view, the present invention contemplates the provision of a standard governor casing mounted on the shaft of a motor which is to-be regulated by the governor. A sealed casing or can in which the governor contacts are mounted, is eccentrically mounted within the casing. The governor contacts consist of afixed contact secured within the sealed can and amovable contact pivotally'mounted within the aforesaid can. A spring is utilized to maintain the movable contact in normal engagement with the fixed contact, until the biasing elfect of the'spring is overcome by the action of centrifugal force acting upon the mass of movable contact. An adjusting linkage is eccentrically secured to the outside of the sealed can and is provided for the purpose of rotating the sealed can about its axis of rotation to'orient the governor contacts with respect to the axis of'rotation'of the governor casing; The movement of the governor contacts with respect to the axis of rotation of the governor results in a change in the direction of application of thecentrifugal force to the movable" governor contact to overcome the efiect of" the biasing' spring" and hence the effective component of the centrifugal force tending to" open the movable contact between the mass of the gov- 2,697,753 i atented Dec. 21, 1954 is varied upon each change in position of thegovernor contacts to cause the movable governor contact to open at various predetermined speeds.

Other objects and advantages of the invention may be readily ascertained from the following detailed description when considered in conjunction with the accompanying drawings wherein: I

Fig. 1 is a side elevational view, partially in section, showing the principal elements comprising the invention;

Fig. 2 is a cross sectional viewtaken approximately along line 22 of Fig. 1 and looking in the direction indicated by the arrows: I

Fig. 3 is a side elevational view of the sealed can containing the governor contacts; and

Fig. 4 is a side elevational view of the governor showing the governor contacts in three different adjusted positions and further, a vector diagram of the centrifugal force acting on the movable governor contact in each of the three positions.

Referring to the drawings and more particularly to Figs. 1 and 2 there is shown a shaft 10 mounted for rotation by any suitable source of rotative power such as an electric motor which is to be governed. The shaft 10 carries a flanged disc or drum or casing 11 which provides a suitable housing for the elements of the governor comprising the invention. Positioned within the casing 11 is a sealed can 12 secured to a stud shaft 13 rotatably mounted within the side wall of the casing 11. A movable contact lever 14 is mounted for pivotal movement on a pin 15. Secured to the contact lever 14 is tension spring 16 having its free end fastened to the inner wall of the sealed can 12 to provide a biasing effect to the contact lever 14 to normally maintain a contact element 17 in engagement with a fixed contact elementlS it is to be noted that the contact lever 14, as shown in Fig. l, is positioned within a plane which is tangent to the arc of rotation of the point on the contact lever 14 which is closest to the axis of rotation of the governor.

A link 21 is secured at one end, in an eccentric manner, to the outer wall of the sealed can 12 by a pivot screw 22. The link 21 is pivotally secured at its free end to a link 23 which has an enlarged head 24, formed on its free end, positioned and held within a slot formed in an adjusting screw 26. The adjusting screw 26 is adapted to be threaded within a threaded aperture contained in an abutment 27 projecting from the flanged rim of the casing 11. A cover 28 is'provi'ded to engage and be secured to the flanged rim portion of the casing 11 to complete the housing for the various component elemental parts of the governor.

It may be therefore appreciated that if the screw 26 is adjusted by means of a knurled head 29, formed integral therewith, the link 23 is reciprocated either upward or downward depending-upon whether the screw 26 is tightened or loosened. Movement of the link" 23 is imparted to link 21 to cause pivot screw 22 to rotate the sealed can 12 about the stud 13. Since the positions of the contacts 17 and 18 are controlled by the position of the can 12, movement of the can 12 causes the contact element 17 and 18 to rotate about the stud 13. it is also to be noted at this time that when the contact elements 17 and 18 rotate about the stud 13 the elements assume a new angular orientation with respect to the shaft 10 and particularly that the contact lever 14 moves from the afore-mentioned tangential plane.

The electrical connections for the contact elements 17 and 18' are shown in Figs. 2 and 3. A lead 33 interconnects thernov'able contact'17 with an arcuate conductorsegment 34 secured to the outer face of the sealed can 12. The stationary contact 18 is interconnected by a lead 36 to a second arcuate segment 37 secured to the outer side wall of the can 12. The arcuate segments 34 and 37 are adapted to engage a pair of spring contacts 38 and 39 secured to the inner surface of the cover 28 of the cylindrical casing 11. Suitable leads 41 and 42' are provided to connect the spring conta'c 33 and 39 to apair of slip rings 43 and 44 respectively. The slip rings 43 and 44 engage a pair of brushes 46 and'47, respectively, connected within a motor control circuit 48 in any well known manner. When the can 12 is rotated by adjusting the screw 26, the spring contacts 38 and 39 move over the arcuate segments 34 and 37 to maintain the governor contact elements 17 and 18 within the motor control circuit 48 for all adjusted positions of the can 12. The details of the motor control circuit are not shown in the present disclosure since their inclusion is deemed unnecessary for a complete understanding of the present invention.

The theory of operation of the present invention may be readily understood by a consideration of the following vector and mathematical analysis of the centrifugal force acting on the movable contact 17. This analysis may be further inhanced by referring to Fig. 4 of the drawing in conjunction with the following discussion.

Whenever the casing 11 and the elements therein are rotating, the centrifugal force F acting on themovable contact 17 equals ma where m is mass of the movable contact 17 and a is the acceleration of the mass 17; but, the acceleration of the moving mass 17 in a circular path toward the axis of rotation is equal to where v is the linear velocity of the center of gravity of the mass 17 and r is the distance from the center of gravity of the mass 17 to the axis of rotation of the cylindrical casing 11. However, the linear velocity of the moving mass 17 in a circular path is equal to m where w is the angular velocity in radians. Substituting in the original equation we have:

In Fig. 4, the centrifugal force F acting on the movable contact 17, in the solid line or normal position a, is designated by the vector Fa. It is to be observed that the direction of the centrifugal force is not in direct opposition to the direction of application of the force exerted by the spring since the force exerted by the spring 16 is perpendicular to the contact lever 14 whereas the direction of application of the centrifugal force is at an angle to contact lever. Therefore, resolving the centrifugal force into components, the component Foa, acting in opposition to the direction of the application of the force exerted by the spring 16, is at an angle to the direction of application of the centrifugal force. gontinuing the mathematical analysis of the forces, we

ave:

Therefore, when the component Foa becomes sufficiently large, the effect of the spring 16 is overcome and the movable contact 17 moves from engagement with the stationary contact 18 to interrupt the motor control circuit 48, causing the motor connected to shaft to be slowed down until the angular velocity u is reduced to permit the movable contact 17 to again move into engagement with the contact 18.

In order to adjust the governor, so that the movable contact 17 Will open at increased angular velocities, it becomes apparent by inspection of Equation 6 the radius r or the value of the cosine of the angles 0 must be decreased to compensate for the increased angular velocity to be imparted to the governor. It is to be remembered that the component FD necessary to open the contact remains constant at all times because the force of the spring 16, tending to close the contact 18, remains constant at all angular velocities.

Considering now the efiect of the movement of the adjusting screw 26 on the factors included in Equation 6, the movement of the screw 26 downwardly, as viewed in Fig. 4, causes the can 12 to rotate to thereby move the contacts 17 and 18, the contact lever 14 and the spring 16 to the dotted line position b. The effect of such a movement is to increase the distance -r from the center of gravity of the movable contact 17 to the center of rotation of the casing 11, consequently the centrifugal force imparted to the contact 18 is increased because from Equation 3 it was shown that the centrifugal force F varies directly with the distance r. This force, of increased magnitude, is represented in Fig. 4 by the vector Fb. However, the assumption of the elemental parts in the new position results in a new angular relationship existing between the direction of the centrifugal force Pb and its component Fob tending to open the contact against the effect of the spring 16. Upon examination of the vector diagram, it is noticed that the angle 9 has increased considerably, hence the value of the cosine function of this new angle 0b is greatly less than the value of the cosine of the angle 0a,.

Therefore, in order to produce a component Fob of sufiicient magnitude to overcome the effect of the spring 16, it becomes necessary to impart a considerably larger centrifugal force Fb to the movable contact 17. Though the distance r increased slightly to increase the centrifugal force this is not sufiicient to allow the contact 18 to open at the same angular velocity at which it opened in position a, because the value of the cosine of the angle 0 drops at a much greater rate than the increase in the distance r. Manifestly, the only way a sufficient centrifugal force can be imparted to the contact 17 is to increase the angular velocity. Therefore, in position b the contact 17 will only open after an increased angular velocity is imparted to the contact.

In the extreme situation (position 0) where the contact lever 14 is in a line parallel with the direction of the application of the centrifugal force Fe or in other words the contact 17 is in a radial position, the magnitude of the force Foe tending to open the contact 18 is zero because the force would act at a right angle to the direction of the centrifugal force and as the cosine of is zero, the value of the component Foo is also zero. Consequently, in position 0, the contact 18 will remain closed at all speeds.

In summarizing the foregoing analysis, it may be readily appreciated that the contact 17 may be made to open at any desired angular velocity by merely adjusting the screw 26 to change the distance r and, most important, to change the angle 0 between the direction of the centrifugal force and the direction of the component of the centrifugal force tending to open the contact 17 against the effect of the spring 16. When the screw 27 is tightened, the distance r increases but the angle 0 also increases to reduce the effective component tending to open the contact 17; hence, the contact does not open until an increased angular velocity is imparted to the governor. When the screw 26 is loosened, the distance r decreases but the angle 0 also decreases, resulting in a much larger component of centrifugal force being imparted to the contact 17; hence, the contact opens at a much lower angular velocity of the governor.

In use of the governor it is contemplated to fill the sealed can 12 with an oil or inert gas to reduce arcing between the contacts 17 and 18, when said contacts open and close. It is believed that the contacts, submerged in oil, will be maintained cleaner and cooler and that vibratory chatter due to the opening and closing of the contacts will be substantially reduced by the dampening action of the oil.

It is to be understood that the above described construction of apparatus and arrangement of elemental parts are simply illustrative of the application of the principles of the invention and many other modifications may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. In a speed responsive governor, a contact arm movably mounted within the governor, a first contact mounted on said arm, a second contact, means for urging the contact arm to bring the first contact into engagement with the second contact against the eifect of centrifugal force, and means for simultaneously varying the angular position of the second contact and contact arm with respect to a predetermined radius of rotation of the governor to vary the effective component-of centrifugal force tending to move the contact arm and the first contact from engagement with the second contact.

2. In a centrifugal governor including a centrifugally responsive contact, means for mounting the centrifugally respons ve contact within the governor within a plane tangential to an arc of rotation of the governor, a fixed contact, resilient means for maintaining the centrifugally responsive contact in engagement wtih the fixed contact, and means for moving the centrifugally responsive contact from the tangential plane to a plane radial to arc of rotation of the governor whereby the effective component of centrifugal force tending to move the contact is progressively decreased to zero when the contact is in the radial plane, said moving means being also effective to move the fixed contact and resilient means whereby the fixed contact is maintained in engagement with the centrifugally responsive contact and the force exerted by the resilient means remains constant.

In a centrifugal governor for an electric motor, a drum adapted to be rotated by the motor, a casing eccentrically mounted within the drum, a fixed contact secured to the casing, a second contact movably mounted within the casing and adapted to cooperate with fixed contact, a linkage eccentrically connected to the casing, and means to actuate the linkage to cause the casing to rotate relative to the drum.

4. In a centrifugal governor, a driving shaft, a casing mounted on the shaft, a centrifugally controlled contact movably mounted with respect to the casing, a second contact adapted to cooperate with the first contact, means for urging the centrifugal contact into engagement with the second contact, and means to vary the angular position of both contacts with respect to the arc of rotation of the driving shaft to vary the effect of the centrifugal force acting on the first contact.

5. In a centrifugal governor comprising a centrifugally responsive contact positioned within a plane tangential to the arc of rotation of the governor, means for maintaining the centrifugal contact stationary against the effect of a predetermined centrifugal force, and means for moving the contact from the tangential plane to a plane radial to the arc of rotation of the governor whereby the component of the centrifugal force tending to move the contact against the effect of the maintaining means is progressively decreased as the contact is progressively moved from the tangential to the radial plane.

6. In a centrifugal governor, a casing, a member movably mounted within the casing and eccentric to the axis of rotation of the casing, a first contact movably mounted on the member, a second contact fixed to the member, means for urging the first contact into engagement with the second contact, means for rotating the member to orient the contacts with respect to the arcs of rotation of the contacts whereby the effective component of centrifugal force tending to move the movable contact from engagement with the fixed contact is accordingly varied.

7. In a centrifugal governor, a drum, a casing rotatably mounted within drum, said casing being mounted eccentrically with respect to the axis of rotation of the drum, a centrifugally actuated contact arm pivotally mounted within the casing, a contact fixed to the casing, means for urging the arm against the effect of the centrifugal force into engagement with the contact, and means for rotating the casing to orient the arm and contact with respect to the axis of rotation of the drum to vary the effective component of centrifugal force tending to move the contact arm against the effect of the urging means.

8. In a centrifugal governor including a drum having a casing rotatably mounted therein, a contact arm movably mounted within the casing, said arm positioned within a plane which is tangent to an arc of rotation of the drum, a fixed contact secured to the casing, resilient means exerting a force perpendicular to the arm whereby the arm is maintained in contact with the fixed contact against the effect of a predetermined centrifugal force, means for moving the arm out of the tangential plane toward a plane radial to the axis of rotation of the drum whereby the centrifugal force necessary to move the contact arm against the effect of the resilient means progressively increases as the arm approaches the plane radial to the axis of rotation of the drum.

9. A centrifugal governor comprising a driven drum, a casing rotatably mounted in an eccentric manner within the drum, a first contact secured to and within the casing, an arm pivotally mounted on and within the casing, a

second contact secured to the arm, resilient means for normally urging the second contact into engagement with the first contact, a linkage mechanism attached to the casing, and means for moving the linkage to rotate the casing to vary the plane of the arm between a plane tangential to the arc of rotation of the drum to a plane which is radial to the axis of the drum.

10. in a centrifugal type governor, a driving shaft, a first casing secured to the driving shaft, a second casing, means for movably mounting the second casing on the first casing in an eccentric manner, a centrifugally operated contact mounted within the second casing, a fixed contact mounted within the second casing, means for urging the centrifugal contact into engagement with the fixed contact against the effect of a predetermined centrifugal force, and means for moving the second casing to vary the angular position of the urging means and contacts so that the effective component of the centrifugal force tending to open the centrifugally operated contact is varied in accordance with the movement of the second casing.

11. In a centrifugal governor, a movably mounted contact, a fixed contact, means for maintaining the movably mounted contact in engagement with the fixed contact against the effect of centrifugal force, said movably mounted contact and maintaining means being positioned so that the component of centrifugal force tending to move the movably mounted contact from the fixed contact equals mw r cos 0 where m is the mass of the contact, to is the angular velocity of the governor, r is the distance between the center of the mass of the contact and the axis of rotation of the governor, and 0 is the angle between the direction of application of the centrifugal force and the direction of application of the component of centrifugal force actin against the force of the maintaining means, and means for simultaneously varying the position of both contacts to vary the angle 0 to vary the effective component of the centrifugal force tending to move the movably mounted contact from the fixed contact.

12. In a centrifugal governor, a movably mounted contact, a fixed contact, means for maintaining the movably mounted contact in engagement with the fixed contact against the effect of centrifugal force, said movably mounted contact and maintaining means being positioned so that the component of centrifugal force tending to move the movably mounted contact from the fixed contact equals mw r cos 0 where m is the mass of the contact, in is the angular velocity of the governor, r is the distance between the center of the mass of the contact and the axis of rotation of the governor, and 0 is the angle between the direction of application of the centrifugal force and the direction of application of the component of centrifugal force acting against the force of the maintaining means, and means for simultaneously varying the position of both contacts to simultaneously vary the angle 0 and the distance r to vary the effect of the centrifugal force tending to move the movably mounted contact from the fixed contact.

13. In a centrifugal governor, a movably mounted contact, a fixed contact, means for urging the movably mounted contact into engagement with the fixed contact, and means for decreasing the radius of rotation of both said contacts and simultaneously orienting said contacts and urging means with respect to the axis of rotation to increase the effective component of centrifugal force tending to move the movably mounted contact.

14. In a centrifugal governor, a movably mounted contact, a fixed contact, means for urging the movably mounted contact into engagement with the fixed contact, and means for increasing the radius of rotation of both said contacts and simultaneously orienting said contacts and urging means with respect to the axis of rotation to decrease the effective component of centrifugal force tending to move the movably mounted contact.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,349,871 Lambert May 30, 1944 FOREIGN PATENTS Number Country Date 868,884 France Dec. 31, 1940 

